An agricultural harvester known as a “combine” is historically termed such because it combines multiple harvesting functions with a single harvesting unit, such as picking, threshing, separating and cleaning. A combine includes a header which removes the crop from a field, and a feeder housing which transports the crop matter into a threshing rotor. The threshing rotor rotates within a perforated housing, which may be in the form of adjustable concaves and performs a threshing operation on the crop to remove the grain. Once the grain is threshed it falls through perforations in the concaves onto a grain pan. From the grain pan the grain is cleaned using a cleaning system, and is then transported to a grain tank onboard the combine. A cleaning fan blows air through the sieves to discharge chaff and other debris toward the rear of the combine. Non-grain crop material such as straw from the threshing section proceeds through a residue system, which may utilize a straw chopper to process the non-grain material and direct it out the rear of the combine. When the grain tank becomes full, the combine is positioned adjacent a vehicle into which the grain is to be unloaded, such as a semi-trailer, gravity box, straight truck, or the like; and an unloading system on the combine is actuated to transfer the grain into the vehicle.
More particularly, a rotary threshing or separating system includes one or more rotors which can extend axially (front to rear) or transversely within the body of the combine, and which are partially or fully surrounded by a perforated concave. The crop material is threshed and separated by the rotation of the rotor within the concave. Coarser non-grain crop material such as stalks and leaves are transported to the rear of the combine and discharged back to the field. The separated grain, together with some finer non-grain crop material such as chaff, dust, straw, and other crop residue are discharged through the concaves and fall onto a grain pan where they are transported to a cleaning system. Alternatively, the grain and finer non-grain crop material may also fall directly onto the cleaning system itself.
A cleaning system further separates the grain from non-grain crop material, and typically includes a fan directing an airflow stream upwardly and rearwardly through vertically arranged sieves which oscillate in a fore and aft manner. The airflow stream lifts and carries the lighter non-grain crop material towards the rear end of the combine for discharge to the field. Clean grain, being heavier, and larger pieces of non-grain crop material, which are not carried away by the airflow stream, fall onto a surface of an upper sieve (also known as a chaffer sieve) where some or all of the clean grain passes through to a lower sieve (also known as a cleaning sieve). Grain and non-grain crop material remaining on the upper and lower sieves are physically separated by the reciprocating action of the sieves as the material moves rearwardly. Any grain and/or non-grain crop material remaining on the top surface of the upper sieve are discharged at the rear of the combine. Grain falling through the lower sieve lands on a bottom pan of the cleaning system, where it is conveyed forwardly toward a clean grain auger.
The clean grain auger conveys the grain to a grain tank for temporary storage. The grain accumulates to the point where the grain tank is full and is discharged to an adjacent vehicle such as a semi trailer, gravity box, straight truck or the like by an unloading system on the combine that is actuated to transfer grain into the vehicle.
Some grain tanks are equipped with movable grain tank covers that move relative to the grain tank and can expand the capacity of the grain tank, in addition to covering the grain tank when the combine is not operating. Grain tanks can also include a bubble up auger, which redistributes the grain within the grain tank to allow for a more even level of grain within the grain tank. The bubble up auger can be mounted or otherwise linked to one of the grain tank covers so that as the grain tank cover raises and descends, the bubble up auger also raises and descends. This allows the position of the bubble up auger to be adjusted as the grain tank covers are adjusted. When the bubble up auger is mounted to one of the grain tank covers, it is imperative that this grain tank cover closes before the other grain tank cover without the bubble up auger. If the grain tank cover without the bubble up auger reaches the closed position first, serious secondary damage can occur from contact between the grain tank cover and the bubble up auger.
Normally, the closing sequence of the grain tank covers is suitable to ensure the grain tank cover with the mounted bubble up auger closes first. However, under certain conditions the closing sequence is not sufficient to ensure that the grain tank cover with the mounted bubble up auger closes first. Such conditions can be the combine being on a sloped surface such that the grain tank cover and mounted bubble up auger have to be closed against the slope or wind conditions that blow against the grain tank cover and mounted bubble up auger opposite to the closing direction. In these conditions, the risk of damage to components of the combine due to the grain tank cover without the bubble up auger closing first is elevated.
What is needed in the art is an agricultural harvester that can close the grain tank covers in the proper order regardless of the operating conditions.